Dysplasia

Dysplasia (from the Greek δυσπλασία "malformation", δυσ- "mal-" + πλάθω "to create, to form"), is a term used in pathology to refer to an abnormality of development. This generally consists of an expansion of immature cells, with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic process. The term dysplasia is typically used when the cellular abnormality is restricted to the originating tissue, as in the case of an early, in-situ neoplasm.

Dysplasia, in which cell maturation and differentiation are delayed, can be contrasted with metaplasia, in which cells of one mature, differentiated type are replaced by cells of another mature, differentiated type.

The terms hip dysplasia and fibrous dysplasia also refer to abnormal development, but at a more macroscopic level.